Manic depressive illness is a familial disorder with a generally acknowledged biogenetic component. Through studies of bipolar patients and their families, it is possible to learn more about the manner in which genetic predisposition may interact with psychocultural mechanisms of transmission to precipitate the disorder. The research efforts of the Unit of Family Studies were focused in the following areas: collaborative studies of the cognitive and emotional development of children born to families where one parent has bipolar disorder; studies of early nurturing patterns of parents of infants at risk; follow-up and outcome studies of rapid-cycling bipolar patients; studies of psychosocial factors associated with seasonal affective disorders; a study of themes and therapeutic factors found in two groups of symptomatically distinct married bipolar patients; and a study of rapid cycling patients who may have a vulnerability to the development of multiple sclerosis. A study of the nurturing attitudes and practices of a group of bipolar patients and their infant children confirmed hypotheses reported in earlier studies regarding the influence of the early rearing environment of the potential manic depressive patient. A study of rapid cycling patients who may be vulnerable to multiple sclerosis continues with a focus on examining family pedigrees in order to assess the absence or presence of neurological disorders. A preliminary case report is in press. Follow-up studies of rapid cycling and seasonal disorder bipolar patients are continuing.